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Dec. 12, 2012 -- Heavy coffee drinkers -- those who drink more than four cups a day -- may cut their risk of dying from cancers of the mouth and throat by nearly half, according to new research.

"We examined coffee drinking habits in nearly 1 million men and women," says Janet Hildebrand, MPH, an epidemiologist with the American Cancer Society.

"Those who reported drinking at least four cups per day of caffeinated coffee incurred about half the risk of dying from mouth and throat cancers compared to people who did not drink caffeinated coffee daily or only drank it occasionally."

That link held even when the researchers took into account smoking habits and alcohol use.

Smoking and alcohol use are among the strongest risk factors for oral cancers.

About 35,000 new cases of oral cancers are expected in the U.S. this year, with 6,800 deaths, according to the American Cancer Society. The new study is published online in the American Journal of Epidemiology.

Previous research by others has linked drinking more than four cups of coffee a day to about the same risk reduction in getting a diagnosis of oral cancer.

Coffee & Oral Cancers: Study Details

Hildebrand's team evaluated more than 968,000 men and women enrolled in the Cancer Prevention Study II. It began in 1982 and is overseen by the American Cancer Society.

At the start of the study, all men and women were free of cancer. During the 26-year follow up, 868 deaths from oral or throat cancers occurred.

The researchers evaluated the coffee- and tea-drinking habits of the men and women. They found the link between coffee and a reduced risk of dying from oral cancers.

More than 97% of the men and women drank either coffee or tea. More than 60% said they drank at least a cup a day of caffeinated coffee.

Among those who drank regularly, most had three cups a day.

The risk reduction of nearly half was similar for those who drank four, five, or six cups daily. Beyond seven cups, Hildebrand says, there weren't enough people to gauge the effect on risk accurately.

Hildebrand found only a suggestion of a link between those who drank more than two cups of decaf daily.

The researchers can't be sure in this study whether the coffee lowered the risk of getting the cancers or improved the odds of survival once cancer occurred. The study only looked at deaths, not the diagnosis.

"We're not recommending people start to drink coffee or that people increase their coffee [intake] for cancer prevention," Hildebrand says. "Much more epidemiological and scientific and clinical evidence would be needed to support such a recommendation."

Coffee & Oral Cancers: Perspective

The new findings are ''fascinating and remarkable," says Joel Epstein, DMD. He is director of oral medicine at the City of Hope Comprehensive Cancer Center, located outside Los Angeles. He reviewed the study findings.

"It seems like there is a significant theme,'' he says, citing several other studies finding a lower risk of various cancers in coffee drinkers. "They are large studies," he says, usually funded by reputable organizations such as the American Cancer Society.

By and large, the studies are coming up with the same findings, he says, even though the researchers study different populations and different cancers. That's a good sign, he says.